Carburetor



Aug. 13, 1935. T. LINGA CARBURETOR Fi led Aug. 7, 1953 2 Sheets-Sheet l Au 13, 1935. UNGA 2,010,956

cARBuRETbR Filed Aug. '7, 1933 2 Sheets-Sheet 2 carburetor or UNITED STATES. PATENT OFFICE CARBURETOR.

Torbjorn Linga, Kokomo, Ind. Application August '1, 1933, Serial No. 683,934 14 Claims. (Cl. 261-72) The present invention relates to carburetors and concerns more particularly the type of such appliances adapted and capable of supplying fuel to. the internal-combustion engine of an automobile from a fuel supply tank ordinarily at 'a' lower level than the carburetor without the employment of any separate auxiliary means, such as a pump ora, vacuum tank.

One leading object of the invention is to provide a carburetor with means to assure that a suitable quantity of fuel will always be present in its float-chamber regardless of whether the fuel supply tank is on the same level as the is at a reasonable distance or height above or below such level.

In the ordinary automobile using a carburetor directly associated with the engine at the front of the vehicle and a fuel supply tank at its rear,

I invention the desired object isaccomplished by theremay well be a distance of ten or more feet between such carburetor and the supply tank, and when such an automobile is traveling on a level road the supply tank might be at about the same level as the carburetonwhereas when the vehicle is traveling up a steep incline the carburetor might be-four or five feet above the supply tank, while when the vehicle is descending the hill the supply tank might be a similar disof the fuel elevating requirementssubstantially at each particular moment; or, stated in other words, if the vehicle is traveling on a.- level road the carburetor would maintaina suction in the float chamber of, for example, 10 to 15 inches of water, and would automatically increase this suction to whatever might be required when the vehicle is ascending a hill.

The advantage of a carburetor constructed on this principle, as compared with an appliance in .which a constant suction is maintained in the fuel chamber adequate to cover the maximum requirements as to fuel lift is the increased volu metric efficiency obtained vof the motor. .In the improved carburetor incorporating this regulating the suction in the float chamber by the float itself or by the fuel level which determines the position of the float.

In order to enable those skilled inthis art to understand this invention fully both from structural and functional standpoints, in the accom- 5 panying drawings, forming a part of this specification and to which reference should be had in connectionwith the following detailed description, a present, preferred embodiment of the invention has been shown, and, for simplicl0 ity, like reference numerals have been used to designate the same parts of the structure in the several views.

In these drawings:

Figure 1 is a central, longitudinal section 15 through the improved andnovel carburetor;

Figure 2 is an upright section on line 22 of Figure 1;

Figure 3 is a vertical section on line 33 of Figure 4; and

,Figure 4 is a top plan view of the carburetor.

' By. reference to these drawings, it will be observed that the appliance includes a suitablyshaped casting providing a main, upright induction-passage l0 equipped at its lower end 25 with a throttle-valve II and at its upper or inlet portion with a balanced, air-admission valve l2, an intermediate section of such passage having a hollow arm l3 in which a downwardlyextended, divided Venturi-tube H is mounted, 30 such arm having an air-inlet passage is leading to the top end of the venturi'and also having a smaller fuel conduit l6 connecting with the circular gap inthe venturi.

w A float-chamber I! also forms part of such 35. casting and at its lower portion it has a fueladmission pipe I8 connected thereto and fltted with an appropriate check-valve l9,-the bottom of the chamber having. a valve-port 2| with which a conical valve 22 coacts to establish and- 40 break connection between the fuel-inlet pipe l8 and the interior of the chamber.

A tube or pipe 23 extends downward from the top wall of the float-chamber to near the bottom thereof, the upper part of such tube being in communication with the fuel-passage l6 through a ported disc 24 in the aperture of which a needle-valve 25 is located.

From the foregoing it will be apparent that the air flowing downwardly through the Venturi-tube occasioned by the suction present in b the main induction-passage I0 imposes an increased suction in passage IE to draw the liquid fuel out of the float-chamber through tube 23,.

the port of valve-disc 24. and passage l6 into the flce 21 fitted with a ball-valve 28 connects the upper portion of the float or fuel chamber with passage Hi, all as is clearly presented in Figure 3. q r

From this description it will be observed that the suction in passage IE will be substantially greater than that in passage I because of the Venturi construction employed, and, due to the use of the two ports'or orifices 26 and 21, this suction in the fuel or float chamber will be determined in relation to the respective suctions in the passages l0 and I6, by the relative areas of the metered ports 26 and 21.

Chamber I 1 houses a float29 mounted fixedly on a sliding rod or stem 3! which at itslower end carries the fuel-inlet valve 22, the upper part of such rod being guided for reciprocation in a bearing 32 in the top wall of the chamber, such wall being formed with a cylindrical vertical passage 33 larger in diameter than, and accommodating, the upper terminal portion of the rod or stem, one upright wall of such pas-' sage being vertically slotted or ported at 34, the

- of the slot or port 34.

As is most clearly illustrated in Figure 2, the

lower, marginal flange of a rubber, sheet-metal, or other appropriate flexible bellows 38 is clamped by a 'ring 39 and its securing screws 4i, 4! against the upper face of the top wall of the fuel or float chamber l1, so that the bellows encloses port 34, valve 35 and associated parts, the,

top, flat wall of the bellows being secured be-. tween outer and inner stiffening and strengthen- 7 ing discs 42, 43, as is usual practice, the two discs and their associated part of the bellows being connected by a rod or link 44 to one arm 45 of a hub 46 secured to the rock-shaft of the'airinlet valve II.

In the chamber or compartment formed by the top wall of the fuel or float chamber and the beilows, a coiled expansion spring 41 is used, resting at its lower end on such top wall and pressing at its upper end upwardly'against the flat wall of the bellows, this spring serving to provide an initial or minimum suction in the air-induction passage l0 and a corresponding au mented suction in the float or fuel chamber H.

A second arm 48 of the hub 46, carries an adjustable .screw 49, the lower end of which bears on the head 5| of the long stem 52 of the fuel aoiaooc needle-valve 25, such stem being vertically slidable in a bearing in a' sleeve 53' appropriately mounted in the main casting of the carburetor in alignment with the ported disc 24, a spring 54 surrounding the sleeve and bearing at its lower end on a shoulder thereof and pressing upwardly at its other end against the head of the valvestem, thereby tending normally to raise the needle-valve and correspondingly open the port of the associated valve-member 24.

Spring 41 is of such strength that it will assure a predetermined, minimum suction present in the float-chamber and, if the internal-combustion engine to which the carburetor is coupled is not running, such, spring will keep valve l2 closed.

It will be noted that owing to the specified connection between the air-inlet valve I2 and the needle-valve 25, as the former is opened the latter will be correspondingly lifted to allow a proportionately greater amount of fuel to flow through the port of disc 24.

Assuming that there is no fuel in the floatchamber and that the engine is started in the usual way, a partial vacuum will be at once established in the main induction-passage it, because the air-admission valve l 2 is held closed by the action of spring 41.

Some air, however, will enter the carburetor through the inlet passage l5 and it will flow through the Venturi-tube into passage I0 and on into the engine or motor.

Such air travel through the Venturi-tube will create an augmented or substantially greater degree of suctionAin passages I6, 21 and 26, as well as in the port of member 24, tube 23 and the floatchamber H, with the result that fuel will be lifted into such chamber through the fuel pipe line l8. As soon as the fuel-level ascends in the float chamber to the bottom open end of the fuel-delivery pipe 23, the suction in the latter will immediately raise the fuel therein up to the fuel needleevalve 25 which meters it into the passage it from which it is drawn into the venturi and discharged therefrom, commingled with the air flowing therethrough into the main inductionpassage l0.

Passage or conduit I 6 may be more or less aptly characterized as a fuel-air-passage because, in addition to the fuel entering such passage through the port around the needle-valve, a small volume of air is drawn into the passage through the small, metered orifice 27. V

Because of the suction-increasing mtion of the venturi, the suction created thereby in passage I6 is substantially greater than that in the main induction-passage l0, and, consequently, air will flow from the latter through the small orifice 26 into the float-chamber and from there through the small aperture 21 into the so-called fuel-air passage l6, and at the fuel needle-valve 25 this air will become mixed with the .uel passing by the needle-valve and flow on into the venturi.

As soon as the fuel in the float-chamber reaches the level designated 500, the float-stem 3| will have elevated the ball 35 in the passage 33 to shut off the connection between the outer air and the space in the bellows, with the result that, whenever the suction in such passage I0 is strong enough to overcome the action of spring, the bellows will start to collapse and thereby open the air-admission valve i2, with, of course, a corresponding opening of the needle-valve 25, so

that there will always be a balanced condition;

bellows 30 just suilicient to overcome the force ofthespring.

Whenever valve 35 closes off. the outside airconnection referred to, a free connection through port 34 will be maintained between -the inside of the bellows "and the main induction-passage I0.

Assuming that a spring 41 has been selected of such strength that-it requires l-inches-of-water suction in the bellows to overcome it, as long as the fuel-level in the float-chamber is at, or

nearly up to, the position I00, ball35 closes off carburetor starts up a sufllciently steep grade or incline t require more than the 20-inch suction in the float-chamber to lift the fuel into it and maintain a proper fuel-level, such level will .of course begin to, descend and thefloa't will be correspondingly lowered permitting alike descent of the ball-valve 35 which will soon uncover'at least a part of the port 34 allowing outside air, at least in some degree, to enter the space in the bellows.

It will now require a greater suction in the suction sufliciently for the required fuel lift at I the moment. Thus a suitable quantity of fuel is kept in the float-chamber at all times with a restriction of the passage of air through the carburetor by the action of air-admission valve I2 sufficient only to raise the fuel as needed momentto moment, and this is one of the prime features or outstanding characteristics of a carburetor incorporating the present invention.v

Hence, instead of constantly keeping a suction in such chamber requisite for maximum fuel lift-- ing effect with resulting unnecessarily-high vacuum inthe induction-passage, the suction is viried to meet the changing conditions as they and consequently the degree of vacuum in the induction-passage need not be kept relatively high except under more or less short or momentary exceptional conditions, such as the ascent of the automobile of unusually steep grades.

In the foregoing, example, provision has been made for the maintenance of a certainminimum suction in the induction passage I0, which may be more or less than the specified amount. The put--v 4 pose for establishing such lower limit of suction is to assure a minimum air velocity through the venturi for proper and air.

An important and salient feature of-the novel and improved carburetor is the preservation of a suitable differential between the suction in the and emcient mixing of the fuel float-chamber andthat in the conduit It, as-

there must necessarily be a higher suction in the latter than'in the former, as otherwise a flow of induction-passage to overcome and balance thep u l through the needle-valve orifice could not be action of the spring and such suction will therefore increase, and this increase will be augmented by the venturi, as previously explained, so that the suction in the float-chamber will be increased correspondingly until itis high enough to lift fuel into such chamber, and the fuel-level in the floatchamber will be kept always between the lines I00 v and 200. "It should be noted that the fuel-level in the float-chamber will not always be the same for all positions of inclination of the car, but it will be perceived that the degree of suction is automatically changed as required to provide a proper lifting-power for the fuel under all conditions. v

In ordinary use of the carburetor the fuel-level is maintained at times by the automatic opening and closing of valve 22 and at other times by the movements, of valve'35. Which one or the other of these valves is operative depends on the height of the required fuel lift at any particular moment, and, secondly, on the degree of initial or minimum suction provided for by the use of spring 41. For

instance, if a spring 41 of such strength is chosen that it necessitates 10 inches of water suction .wlthin the bellows to overcome it, then the sucfuel chamber of at least 20 inches. At such times as the required height of fuel lift is less than 20 inches the fuel-level in the float-chamber will be maintained at or near line I00 by theauto;

effected, and this difference in the degree of suction must change because the pressure drop through the air-inlet valve I2 is a variable factor. Due to the suction-increasing characteristic of the venturi, the suction in passage I6 is greater than that in the main induction-passage II and air flows from the passage I0 through the orifice 26 into the float-chamber I1 and from the latter ihrough'aperture 21 into conduit I0 and thence into the venturi. 1

Omaccount of the restricted nature of the two openings 20 and 21, a pressure drop will take place at each. I If, for example, there is a suction of 40 inches of water in conduit I0 and of 20 inches in passage l0, thus making a total pressure drop of 20 inches and, if the orifices are of the same size and there the two metered orifices 26 and 21 of approxi- I mately the same size, we have the following condition present: A pressure drop at orifice 20 of 8 inches, atoriflce 21 of 8% inches and another 3-inch drop on account of the ball-valve, giving a total 0f20-inchdl'0p'.

Consequently, if the: suction in conduit I0 is 40 inches and'inthe main induction passage II is 20 inches, the suction in the float-chamber will be 40 inches minus the 3-inch dropdue to the valve and the 8 -inch drop due to the orifice, whereby the float-chamber suction will be28 inches.

The improved carburetor mayconveniently incorporate other features of construction, for

starting the engine in cold weather, but inasmuch as this forms no important part of the present invention, illustration and description thereof have not beenpresented.

The invention as defined by the appended claims is susceptible of a variety of satisfactory o1 any of the valuable advantages accruing from the employment of the invention.

In this connection it should beborne in mind that whereas in the present, preferred embodiment of the invention a bellows has been shown and described, there are several other mechanical equivalent structures'which can be readily substituted therefor.

The term varyingfuel lifting requirements as used in the appendedclaims should be construed to involve the suction necessary to overcome the resistance whereby to secure the proper flow of fuel from the supply to the carburetor, since this resistance, in addition to the actual difference in height between the supply and carburetor, includes the friction in the fuel line.

I claim:

1." In a carburetor, the combination of an induction-passage, an air-inlet valve for said passage, a fuel-chamber, a fuel-conduit connecting said fuel-chamber to said induction-passage, a

fuel-inlet conduit for said chamber adapted to be connected to a fuel-supply capable of varying its height with relation to that of said chamber, a float in said chamber, and means including said air-inlet valve governed by said float to maintain.

a suction in said fuel-chamber changing automatically to conform substantially to the varying fuel lifting requirements between said fuel-sup ply and fuel-chamber and at any moment sumcient to lift fuel into said chamber under the then existing conditions.

2. In a carburetor, the combination of an induction-passage, a fuel-chamber, a fuel-conduit connecting said chamber and passage, a fuel-inlet conduit for said chamber adapted to be connected to a fuel-supply capable of varying its height with relation to that of said chamber, a float in said chamber, and meansincluding an air-inlet valve for said induction-passage and a pressureresponsive device governed by said float-to maintain a suction in said fuel-chamber changing automatically to conform substantially to the varying fuel lifting requirements between said fuel-supply and fuel-chamber and at any moment suflicient to lift fuelinto said chamber under the then existing conditions.

3. In a carburetor, the combination of a main I induction-passage, a fuel-chamber, a fuel-conduit connecting said chamber and passage, a fuel-inlet conduit for said chamber adapted to be connected to a fuel-supply capable of varying its height with relation to that of said chamber, a float in said chamber, an air-inlet valve for said inductionpassage, a pressure-responsive device to actuate said air-inlet valve, conduit means to connect said device to said induction-passage and to the external air, and a valve governed by said float to control said conduit means of said device to maintain a suction in said fuel-chamber changing automatically to conform substantially to the varying fuel lifting requirements between said fuel-supply and fuel-chamber and at any moment suflicient to lift fuel into said chamber under the then existing conditions.

'4. The construction presented in claim 3 in combination with a valve regulating the fuel-flow through said fuel-conduit, and means connecting said air-inlet and fuel-regulating valves whereby they will both open and close correspondingly.

5. In a carburetor, the combination of a main induction-passage, a fuel-chamber, a fuel-inlet conduit for said chamber adapted to be connected to a fuel-supply capableof varying its height with relation to that of said chamber, means to increase the suction developed in said inductionpassage, means to apply a portion only of said increased suction. to said fuel-chamber cally change the suction in said fuel-chamber to conform substantially to the varying fuel lifting requirements between said fuel-supply and fuelchamber whereby the suction in said chamber at any moment will be suflicient to lift fuel into said chamber under the then existing conditions.

6. In a carburetor, the combination of a main induction-passage, an air-inlet valve for said passage, a suction-increasing venturi in said passage, a conduit connecting said venturi to the external air, a fuel-chamber, a fuel-inlet conduit for said chamber and adapted to be connected toa fuel-supply capable of varying its height with relation to that of said chamber, a float in said chamber, a bellows, means connecting said bellows to said air-inlet valve whereby contraction and expansion of said bellows opens and closes said air-inlet valve, a spring acting on said bellows, conduit means connecting the *interior of said bellows to the outer air and to said induction-passage, avalve controlling said bellows conduit means, means whereby said float actuates said last-mentioned valve, a fuel-conduit leading from said chamber to the suction-increasing portion of said venturi, a fuel-valve in said fuel-conduit, and means connecting said air-inlet valve and said fuel-valve to compel their movements to be simultaneous and corresponding, the carburetor having a metered orifice connecting said induction-passage to the interior of said chamber and another metered orifice connecting the interior of said chamber to said fuel-conduit, whereby a fuel-lifting suction is maintained in said fuel-chamber and which changes automatically to conform substantially to the varying fuel lifting requirements between said fuel-supply and said fuel-chamber and which at any moment is sufiicient to lift the fuel into said chamber under the then existing conditions.

. 7. The construction presented in claim 6 in combination with a valve in said fuel-inlet conduit, and means to operate said valve by said float.

8. In a carburetor, the combination of a fuelchamber, a fuel-inlet conduit for said chamber adapted to be connected to a fuel-supply capable of varying its height with relation to that of said chamber, a fuel and air mixing structure having means to admit air to said structure, means to deliver fuel from said fuel-chamber to said structure, means to subject said fuel-chamber to suction to raise the fuel through said conduit into said chamber, means actuated by change of fuellevel in said chamber to vary said fuel-chamber suction and to maintain the fuel-level in said chamber within predetermined limits, and means operated by said fuel-level-change actuated means to control the infiowof fuel into said chamber when the fuel-supply is above said chamber.

9. In a carburetor, the combination of an induction-passage having air-inlet means, a valve controlling at least a portion of said air-inlet means, a fuel-chamber, a fuel-conduit connecting said fuel-chamber to said induction-passage, a fuel-inlet conduit for said chamber adapted to be connected to a fuel-supply capable of varying its height with relation to that of said chamber, means to apply suction induced in the carburetor to the interior of said fuel-chamber, a float in said chamber, and a variable connection between said float and said air-inlet control valve, whereby said air-inlet control valve is governed by said float to change the suction in said fuel-chamber varying fuel-lifting requirements between said fuel-supply and said fuel-chamber.

10. In a carburetor, the combination of an induction-passage having air-inlet means, a valve controlling at least a portion of said air-inlet means, i, means to operate said air-inlet control valve by suction in the carburetor, a fuel-chamber, a fuel-conduit connecting said fuel-chamber automatically to conform substantially to the 11. In a carburetor, the combination of an induction-passage having air-inlet means, a valve controlling at least a portion of said air-inlet means, a fuel-chamber, a fuel-conduit connecting said fuel-chamber to said induction-passage, a fuel-valve in said fuel-conduit, a fuel-inlet conduit for said fuel-chamber adapted to be connected to a fuel-supply capable of varying its height withrelation to that of said chamber, a float in said chamber, means to apply suction induced in the carburetor to the interior of said fuel-chamber, a connection between said floatand said air-inlet control valve, whereby said airinlet control valve is governed by said float to change-the suction in said fuel-chamber automatically to conform substantially to the varying fuel-lifting requirements between said fuel-supply and said fuel-chamber, and means to adjust said fuel-valve automatically coincidentally ,with

the movements of said air-inlet valve.

12. In a carburetor, the combination of a main induction-passage having air-inlet meansfa valve controlling atleast a portion of said. air-inlet means, a fuel-chamber, a. fuel-conduit connect-- ing said fuel-chamber to said induction-passage, a fuel-valve in saidfuel-conduit, a fuel-inlet conduit for said fuel-chamber adapted to be connected to a fuel-supply capable of varying its 5 height with relation to that of said chamber, a float in said chamber, means to increase the suction developed in said induction-passage and to apply said increased suction to the interior of said fuel-chamber, a connection between said float 1 and said air-inlet control valve, whereby said airinlet control valve is governed by said float to change the suction in said fuel-chamber automatically to conform substantially to the varying fuel-lifting requirements between said fuel-sup- 15 duit for said fuel-chamber adapted to be con-\ nected to a fuel-supply capable of varying its height with relation to that of said chamber, a float in said chamber, means to increase the suction developed in said induction passage and to apply said increased suction to the interior of said fuel-chamber, a variable connection between said float and said air-inlet control valve, whereby said air-inlet control valve is governed by said float to change the suction in said fuel-chamber automatically to conform substantially to the varying fuel-lifting requirements between said fuel-supply and said fuel-chamber, and means to adjust saidfuel-valve automatically coincidentally with the movements of said air-inlet control valve.

14. In a carburetor, the combination of a main induction-passage having air-inlet means, a fuelchamber, a fuel-inlet conduit for said fuelchamber adapted to be connected to a fuel-' supply capable of varying its height with relation to that of said chamber, a fuel-conduit connecting said fuel-chamber to said induction-passage, Venturi-means to create suction greater than that in said induction-passage, means to apply said greater suction to said fuel-conduit,

means to maintain suction in the interior of said fuel-chamber to lift the fuel from said supply into said chamber, and means to modulate said fuel-chamber suction automatically to'conform substantially to the varying fuel-lifting requirements between said fuel-supply and said fuelchamber.

TORBJORN LINGA 

